Art is purposiveness without purpose.

Reason must approach nature in order to be taught by it. It must not, however, do so in the character of a pupil who listens to everything that the teacher chooses to say, but of an appointed judge who compels the witness to answer questions which he has himself formulated.

Happiness is not an ideal of reason, but of imagination.

A lie is the abandonment and, as it were, the annihilation of the dignity by man.

An action is essentially good if the motive of the agent be good, regardless of the consequences.

The only objects of practical reason are therefore those of good and evil. For by the former is meant an object necessarily desired according to a principle of reason; by the latter one necessarily shunned, also according to a principle of reason.

A single line in the Bible has consoled me more than all the books I ever read besides.